This invention relates generally to the art of seals, and is concerned in particular with neck seals of the type employed on roll necks in rolling mills.
In a typical rolling mill installation, a roll neck is journalled for rotation in an oil film bearing. The bearing includes a sleeve keyed or otherwise fixed to the roll neck for rotation therewith. The sleeve is surrounded by and supported within a non-rotatable bushing which is in turn contained in a bearing chock. An oil film is maintained between the sleeve and the bushing during operation of the mill. A seal assembly is employed both to prevent loss of oil from the bearing, and also to prevent exterior contaminants such as cooling water, mill scale, etc. from penetrating into the bearing.
Typical of the prior art seal assemblies which have heretofore been developed are those described in U.S. Pat. Nos. 2,868,574; 3,093,425; 3,330,567; 3,545,774 and 3,382,021, all assigned to the same assignee as that of the present invention. These prior art seal assemblies include a neck seal having a flexible circular body mounted on a tapered transition section of the roll neck, with resilient flanges which extend radially outwardly from the seal body. The ends of the resilient flanges are adapted to frictionally contact surrounding shoulders on a non-rotatable seal end plate. Oil is retained in the bearing by the seal provided at the interface between one of the rotating resilient seal flanges and the non-rotatable seal end plate shoulder in contact therewith. Likewise, contaminants are excluded from the bearing by the seal provided at the interface between the other of the rotating resilient seal flanges and its associated seal end plate shoulder. As the resilient flanges of the neck seal wear, seal integrity is gradually compromised, eventually resulting in the necessity to replace the neck seal.
While the above described conventional seal assemblies have operated for many years in a generally satisfactory manner, there have been several problems associated with their use. One such problem relates to the fact that even when the neck seals are new, some leakage may be experienced because of the inability of the resilient flanges to fully compensate for axial and/or radial misalignment of other associated components. Also, rapidity of wear of the resilient flanges on the neck seals, causing eventual loss of seal integrity and necessitating frequent replacements of the neck seals, has been a continuing problem which is expected to become more severe as mill speeds gradually increase.
Accordingly, a general object of the present invention is the provision of an improved neck seal having the capability of either obviating or at least substantially minimizing the problems mentioned above.
A more specific object of the present invention is the provision of an improved neck seal which is capable of more extended periods of use under high speed operating conditions.
Another object of the present invention is the provision of a neck seal having resilient flanges which each have multiple areas of sealing contact with adjacent surfaces of the seal end plate.
A further object of the present invention is to increase the number of areas of sealing contact between the neck seal and its surrounding seal end plate without adversely affecting the ability of the seal assembly to compensate for axial shifting of the roll relative to its bearing chock.
Still another object of the present invention is to provide resilient flanges on the neck seal which make more efficient use of the centrifugal forces developed during roll rotation.